This project will investigate the details of the metabolic pathway of neutral sterols to bile acids, particularly to: a) elucidate the pathway from cholestanol to allo bile acids, b) investigate the details of 12-alpha-hydroxylation in relation to formation of 5alpha- and 5beta-bile acids, c) exploit new methods in HPLC separations of bile acids and establish a computerized data acquisition system for GLC-MS analyses of bile acids and their derivatives. BIBLIOGRAPHIC REFERENCES: Bile Acids. XLVIII. Separation of Conjugated Bile Acids by High Pressure Liquid Chromatography. R. Shaw and W.H. Elliott, Anal. Biochem. 74, 273, 1976. Bile Acids. XLIX. Allocholic Acid. The Major Bile Acids of Uromastix Hardwickii. S.S. Ali, H. Farhat, and W.H. Elliott, J. Lipid Res. 17, 21, 1976.